I. Field of the Invention
The invention relates to handling documents and particularly to the registration of documents on the platen of a photocopier.
II. Description of the Prior Art
It is important to be able quickly and accurately to move documents to a registered position on the platen of a photocopier. Registration of the document is necessary to assure the production of a complete and visually acceptable copy. If the document is situated on the platen in a skewed or misaligned position within the area, the copy will reflect this same skew or misalignment and may be incomplete and/or unacceptable to the user. The avoidance of skew is particularly important in an automatic document handler by which sheets are moved in sequence into a registered position on the platen and then moved out of that position to make way for the next sheet.
In order to reduce the incidence of skew in an automatic document handler, it has previously been proposed to register the document against a stop, the document being driven over the platen surface by a belt drive. Particularly good results have been achieved by apparatus as proposed in copending Application Ser. No. 687,062, filed May 17, 1976 and assigned to the same assignee as the present invention in which the belt is narrow relative to the surface and is centrally located over the surface whereby in operation the belt engages a generally centrally located portion of a document to move the latter over the surface.
The stop conveniently takes the form of a registration strip extending along one edge of the platen. Previously used registration strips which rest on the surface of the platen near the edge suffer from the disadvantage that unless the strip is specially machined or otherwise carefully formed, it will not be in continuous contact with the smooth platen glass. The result of irregularities in the strip is to cause spaces between the strip and the platen in which the edge of a document may become trapped. This problem has in the past been solved by inserting a plastic filler in the gap but an alternative and simpler solution is now proposed.